The current invention relates generally to chippers and grinders, which are devices used to process items into smaller pieces. Chippers typically contain sharp knives that cut items such as whole trees and branches into smaller woodchips. Grinders, on the other hand, typically contain hammers which crush aggregate material into smaller pieces through repeated blows. Example prior art chippers are shown in U.S. Pat. Nos. 8,684,291; 7,637,444; 7,546,964; 7,011,258; 6,138,932; 5,692,549; 5,692,548; 5,088,532; and 4,442,877; and US 2014/0031185, each owned by Vermeer Manufacturing Company; these documents are each incorporated herein by reference in their entirety and form part of the current disclosure. Example grinders are disclosed in U.S. Pat. Nos. 7,441,719; 7,213,779; 7,077,345; and 6,840,471, each owned by Vermeer Manufacturing Company; these patents are each incorporated herein by reference in their entirety and form part of the current disclosure as well.
Chippers and grinders often include in-feed systems for moving items to the knives or hammers to be processed. Some embodiments of the current invention relate particularly to improved in-feed systems for chippers and grinders, to chippers and grinders having such improved in-feed systems, and to methods of operation.